Apparatus for forming and burning gaseous mixtures



Dec. 29, 1931. E. G. BUSCHOW 1,838,903

APPARATUS FOR FORMING AND BURNING GASEOUS MIXTURES Filed Feb. 9, 1928 myz IN VEN TOR.

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5(1 axial alignment with the tu Patented Dec. 29, 1931 UNITED STATES PATENT OFFICE EDWARD G. BUSGHOW, OI PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO SURFACE GOM- BUSTION CORPORATION, OF TOLEDO, OHIO, A CORPORATION OF NEW YORK APPABATUBIOB FORMING AND BURNING GASEOUS MIXTURES Application filed February s, 1928. Serial No. 253,148.

This invention relates to improvements in apparatus for forming aseous mixtures of fuel gas and air and has or its general object to provide in combination with a sin lemixing tube, an arrangement of jet ori ce nozzles such as will permit the nozzlesto be used simultaneously or se arately without mutual interference and wit out adjustment or substitution of jet orifice sizes for obtaining certain results hereinafter more fully set forth.

Other objects of the invention will more fully appear hereinafter.

Referring to the drawings wherein a preferredembodiment of the invention is shown, Fig. 1 is a longitudinal section through the main portion of the apparatus; Fig. 2 is a more orless diagrammatic representation on a reduced scale of the apparatus shown in Fig. 1 in combination with a heat treating furnace, only a fragment of which is shown; and Fig. 3 is an end elevation of the jet orifice nozzle end of the apparatus.

In the drawings, 10 indicates a combined burner and mixing tube of a type well known in the art which I have chosen for the purpose of explaining my invention. However, the mixing tube and burner may be structurally separate pieces of apparatus appropriately connected by suitable piping.

In the apparatus as shown the burner part of the tube 10 has a restriction 12 through which the gaseous mixture of fuel gas and air is discharged into the furnace 19 for burning. Intermediate the ends of the tube is formed a radial flange 18 which serves as a means for securing the burner to a furnace wall 17. Means for dissipating heat from the burner are indicated at 20 and are shown as radial webs or flanges formed on the tube in 'close proximity to the flange 18. The other end of tube. 10 has a flaring mouth 14 as is customary in mixing tubes generally as, for example, in mixing tubes of the Venturi type which in so far as this invention is concerned, the tube 10 might just as well be.

16 indicates a stirrup in front of the mouth of the tube and serves as a support for a barrel 22 which projects throu the stirrup in a. Threadedly secured in one end of the barrel is a gas nozzle 24 having a series of gas jet orifices 26 formed about a central point. Four orifices are shown but a lesser or greater number may be used without departing from the spirit of the invention. The nozzle .is so positioned with respect to the mouth 14 of the mixing tube 10 that the required amount of air may be entrained into the tube by the jets of gas issuing from the jet orifices 26.

Extending from the other end of the barrel 22 is a tubular fitting 28 adapted for connection with a gas pipe 30. The outer end of this fitting is closed by a plug-like body 32 which is provided with an internally threaded bore 33. Supported at one end within the bore of the fitting 32 and at its other end in a central tapered opening in the nozzle 24 is a conduit 40. The nozzle-supported end of the conduit is preferably provided with a structurally separate jet orifice nozzle 42 which makes a gas tight fit with the central opening in the nozzle 24. Extending from the fitting 32 is a tubular fittin 34 with which connects a gas pipe 36. cured in the fitting 34 in alignment with the fitting 32 is a removable plug 38. By removing this plug a cleaning tool or rod can be passed through the conduit and its nozzle for cleaning purposes. The gas pipes 30 and 36 are provided with conventional cut-off valves 46 and 48 respectively. Threadedly mounted on the barrel 22 where it projects into the stirrup 16 is an air shutter 44 which may be adjusted asoccasion demands for regulating the passage of air into the mixing tube 10.

The above described apparatus constitutes a means for obtaining selectively different air gas mixtures by the simple act of manipulating the valves 46 and 48 as will now be explained. It should be first pointed out that the jet orifice nozzle through which theinducing or entrainingconstituent passes into the mixing tube must be of a given size for any given gas in order to obtain a given mixture of gas and air, other factors remaining constant, for exam le, the size of the burner nozzle through which the mixture passes for burning. Changing the size of the jet orifice for the inducing gas to obtain different air.

gas mixtures offers many practical objections, such as non-availability of the proper size of jet orifice and shutting down of the heatmg operation as where a furnace is being heated, to mention only a few of the objections. In accordance with the present invention no change in size of the jet orifice sizes need be made to obtain the different air gas mixtures. It should also be pointed out that different air gas mixtures will upon burning give different kinds of furnace atmosphere as for example, reducing or neutral or oxidizing atmospheres.

In many heating operations one or the other of said atmospheres may be required at different periods. Let us assume that natural gas is available as fuel and that both pipes 30 and 36 are connected to the same sourceof supply and that the jet orifice 42 has a smaller cross sectional area than the combined areas of the jet orifices 26 in nozzle 24. The air gas mixture formed by the entraining action of the jet of gas issuing from orifices 26 will then be richer in gas than the mixture formed by the entraining action of the jet of gas issuing from the orifice 42. Just what the relative richness of the mixtures may be is determined by the character of the furnace atmosphere desired. If the relatively lean mixture is such as to produce a neutral atmosphere upon burning, the richer mixture would when burned give a reducing atmosphere. By allowing t e gas to flow through only one set of the jet orifice nozzles the desired furnace atmosphere at any period of furnace operation can be immediately obtained as will now be readily understood.

In some cases it may be desirable not to form the relatively lean mixture in the manner indicated but rather by supplying more air to the gas rich mixture. This can be accomplished by connecting the pipe 36 to a source of air under pressure and jettin the air into the rich mixture. It may be pointed out at this oint that the shutter 44 would not be capa le of any manipulation tending to permit more air to be entrained into the tube in view of the fact that the size of the orifices is determined with the shutter fully open. The primary purpose of the shutter is to shut off the entry of air into mixing'tube when the burner is to be shut off or lighted in order to prevent back firing.

The apparatus also offers a means for selectively utilizing two different fuel gases with the same mixing tube and without requiring shut down of furnace operation due to changing the jet orifice sizes as would be required if only one jet orifice nozzle were provided. Coke oven gas, for example, may be available but may not be suitable for certain heating operations or may not be available in sufficient quantity at all times. here, however, conditions are such that the coke oven gas is available and suitable for use the present apparatus makes possible such use by the simple act of closing the valve, for example valve 46, which controls the supply of the constantly available and suitable gas such as natural gas and opening the other valve, namely valve 48 in pipe 36, which it may be assumed leads to a source of supply of coke oven gas. By supplying the coke oven gas through the pipe 36 instead of through the pipe 30, cleaning of the flow passages can be readily effected b merely removing the plug 38 in the end oft e fitting 34 and passing a cleaning tool through the conduit 40 and nozzle 42. Coke oven gas it may be mentioned contains tarry matter which necessitates frequent cleaning of the conduits through which it is passed. Except for this fact the coke oven gas could just as well be passed through the nozzles 26. As a matter of fact if two clean fuel gases of different richness are available it would be preferable to use the nozzle 24 with its plurality of jet orifices 26 for the less rich or lean gas because the jet orifices could then be made relatively larger with consequent less liability to clogging.

While I have shown the mixing tube 10 as delivering into a single burner it will be readily apparent that a plurality of burners may be supplied with gaseous mixture from the single mixing tube in which event a suitable manifold would be inserted between the burners and the mixing tube.

It has been pointed out that different amounts of the same gas may be passed through the two sets of orifice nozzles in order to obtain two mixtures which may be used independently. It will be readily appreciated that a still difi'erent mixture may be formed by jetting gas from both sets of nozzles simultaneously. The apparatus therefore offers a means for producing a plurality of gaseous mixtures with a single mixing tube without necessitating any change in nozzle sizes and without interrupting the heating operation.

What is claimed is:

1. In apparatus for producing and supplying a gaseous mixture of fuel gas and air from either of two different sources of supply, the combination of a mixing tube having at its receiving end a flarin mouth, a gas supply conduit -for one of t e gases, 8. member associated with said conduit and forming with said mouth an annular opening through which air may be induced to flow into said tube, said member having formed therein a group of jet orifices through which gas may pass from said conduit into said tube in a manner to entrain air through said annular opening, said member having also a central opening formed therewith, a second gas supply conduit for the other one of said gases, and a nozzle seated in said central opening and connected to said second conduit in such a manner as to discharge gas into said mixa ing tube and to entrain air through said annular opening.

2. In apparatus for producing and supplying a gaseous mixture of fuel gas and air from either of two different sources of supply, the combination of a mixing tube having at its receiving end a flaring mouth, a gas supply conduit for one of the gases, a member removably associated with said conduit and forming with said mouth an annular opening through which air may be induced to flow into saidtube, said member hav ing formed therein a group of jet orifices through which gas may pass from said conduit into said tube in a manner to entrain air through said annular opening, said member having also a central opening formed therein, a second gas supply condult for the other one of said gases, and a nozzle removably seated in said central opening and secured to the outlet end of said second conduit in such a manner as to discharge gas into said mixing tube and to entraln air through said annular opening.

3. In apparatus for producing and supplying gaseous mixtures of fuel gas and alr, from either of two different sources of gas supply, the combination of a mixing tube having at its receiving end a flaring mouth, means forming with said mouth an annular opening through which air may be induced to flow into said tube, means forming a group of gas jet orifices set to discharge into said tube in a manner to entrain air through said annular opening, means including a tube with a straight bore having an independent gas jet orifice set to discharge gas centrally into said mixing tube in a manner to entrain air through said annular opening, a clean out plug in alinement with said bore, means for supplying one of said gases to the group of orifices, and means for supplying the other of said gasesto the other said orifice.

4. An apparatus for forming and burning gaseous mixtures of diiferent fuel value, comprising in combination a single mixing tube with an air inlet and an outlet for the combustible mixture, means including a tube with a straight bore having a relatively large orifice set t9 discharge a central stream ofgas of the lower fuel value into said mixing tube in a manner to entrain air from said air inlet, a clean out plug in alinement with said bore, means for discharging gas of the higher fuel value into said mixing tube in coaxial relation thereto and in a manner to entrain air from said air inlet, and means for selectively supplying gas for either or both gas streams to form a combustible mixture in said mixing tube. V

5. In a gas burner, the combination of a burner conduit having a divergent o ening at its outer end, a bracket supported y the outer end of said conduit a tube supported by said bracket in axial alinement with said conduit, a nozzle concentrically positioned within said tube, a multi-jet nozzle having an opening wherein said nozzle is adapted to seat, said multi-jet nozzle'being secured to the outer end of said tube, and independent supply pipes for the respective nozzles.

In testimony whereof I aflix m signature.

EDWARD G. BU CHOW. 

